DEVICE FOR MEASURING THE DISTANCE TO AN OBJECT

Abstract

Described and shown is a device for measuring the distance to an object, including at least two freely radiating transmitter units for transmitting an electromagnetic measuring signal, at least one receiver unit for receiving a reflection signal reflected on the object, and at least one evaluation unit. The at least one receiver unit forwards the received reflection signal to the at least one evaluation unit. The transmitter units and the at least one receiver unit re arranged within one measuring environment. The transmitter units and the at least one receiver unit have at least one common measuring frequency range. The operation of the transmitter units is coordinated so that the measuring signals transmitted by the transmitter units and the reflection signals resulting from the measuring signals can be differentiated from one another.

Claims

1. A device for measuring the distance to an object, the device comprising: at least two freely radiating transmitter units for transmitting electromagnetic measuring signals, at least one receiver unit for receiving a reflection signal reflected on the object, and at least one evaluation unit, wherein the at least one receiver unit forwards the received reflection signal to the at least one evaluation unit, the transmitter units and the at least one receiver unit are arranged within one measuring environment, the transmitter units and the at least one receiver unit have at least one common measuring frequency range, operation of the transmitter units is coordinated so that the measuring signals transmitted by the transmitter units and the reflection signals resulting from the measuring signals are differentiated from one another, and the at least one receiver unit assigns each of the measuring signals and the reflection signal to a specific one of the transmitter units regardless of an arrangement of the transmitter units.

2. The device according to claim 1, wherein the device comprises a fill level meter for measuring a fill level in a container.

3. The device according to claim 1, wherein each of the transmitter units is simultaneously a respective one of the at least one receiver unit.

4. The device according to claim 1, wherein the measuring signals transmitted by the transmitter units are a pulse-like or frequency modulated radar signal.

5. The device according to claim 1, wherein the operation of the transmitter units among one another is coordinated such that only one of the transmitter units is active at a time.

6. The device according to claim 5, wherein the transmitter units alternately transmit the measuring signals.

7. The device according to claim 5, wherein: the transmitter units each include one said receiver unit, and the operation of the transmitter units is coordinated in such a manner that only a single one of the transmitter units and one said receiver unit is active at a time, and at regular or irregular intervals, only one said receiver unit is active at a time, without the associated one of the transmitter units.

8. The device according to claim 1, wherein a communication cable connects the transmitter units to one another, and the transmitter units exchange data via the communication cable.

9. The device according to claim 1, wherein a wireless interface is provided between the transmitter units, and the transmitter units exchange data via the wireless interface.

10. The device according to claim 1, wherein the measuring frequency range has at least two measuring sub-bands, and the operation of the transmitter units is coordinated such manner that the transmitter units are operated in different ones of the at least two measuring sub-bands.

11. The device according to claim 10, wherein an own calibration kit is provided for each of the at least two measuring sub-bands.

12. The device according to claim 10, wherein the at least two measuring sub-bands do not have a common frequency.

13. The device according to claim 1, wherein: each of the transmitter units is simultaneously a said receiver unit, the measuring frequency range has at least one communication sub-band, and each of the transmitter units and each said receiver unit is designed such that it is operated in the at least one communication sub-band.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a first embodiment of a device according to the invention,

[0035] FIG. 2 is a second embodiment of a device according to the invention, and

[0036] FIG. 3 is an exemplary illustration of the subdivision of the frequency band into measuring sub-bands and a communication sub-band according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0037] A first embodiment of a device 1 for measuring the distance to a surface of a bulk material in a container 12 is illustrated in FIG. 1. The device 1 comprises two freely radiating transmitter units 2, 3 for transmitting an electromagnetic measuring signal 4, 5 in the form of a frequency modulated radar signal, two receiver units 6, 7 for receiving a reflection signal 8, 9 reflecting on the surface of the bulk material, wherein each transmitter unit 2, 3 is designed as a receiver unit 6, 7 and wherein each receiver unit 6, 7 at least partially also receives reflections with its non-identical transmitter unit 2, 3, which is illustrated by the receipt of reflection signals 13 as an example. Furthermore, the device 1 comprises two evaluation units 10, 11 that determine the distance to the surface of the bulk material from the transit time of the received reflection signals 8, 9 and the difference frequency between the received reflection signal 8, 9 and the transmitted measuring signal 4, 5.

[0038] Additionally, the transmitter units 2, 3 and, thus, the receiver units 6, 7 are arranged within one measuring environment. In the illustrated embodiment, the transmitter units 2, 3 and the receiver units 6, 7 are arranged within the same container 12 and measure the distance to the same surface of the bulk material. Furthermore, the transmitter units 2, 3 and the receiver units 6, 7 have an identical measuring frequency range. In order to avoid the transmitter units 2, 3 and the receiver units 6, 7 from influencing one another due to a receiver unit 6, 7 receiving a reflection signal 13 from a transmitter unit 2, 3 that is not identical to it, the operation among the transmitter units 2, 3 is coordinated. The measuring signals 4, 5 can be differentiated from one another and a clear assignment of each measuring signal to a transmitter unit 2, 3 is possible regardless of the arrangement of the transmitter units.

[0039] The communication of the transmitter units 2, 3 among one another and, in this respect, the coordination of the operation of the transmitter units 2, 3, is carried out via a communication cable 14 that connects the transmitter units 2, 3 to one another. In the illustrated embodiment, the operation of the transmitter units 2, 3 is coordinated in such a manner that the transmitter units 2, 3 are operated at frequencies of different measuring sub-bands of the measuring frequency range. In this respect, the measuring signals 4, 5 differ in their frequencies. The receiver units 6, 7 are designed in such a manner that they only receive and forward to the evaluation unit 10, 11 frequencies that are transmitted from the transmitter unit 2, 3 that is identical to the associated receiver unit. Influencing among one another of the transmitter and the receiver units 6, 7 is thus eliminated.

[0040] According to another embodiment, the communication cable 14 is not used in the above-described arrangement.

[0041] In this respect, the embodiment illustrated in FIG. 1 provides a device 1 that, due to the use of several transmitter and receiver units 6, 7, has a particularly high measuring accuracy and a particularly high operating safety, wherein it can be ensured that the transmitter units 2, 3 operate failure-free.

[0042] FIG. 2 shows a second embodiment of a device 1 according to the invention. The illustrated device 1 has three freely radiating transmitter units 2, 3, 15 that are simultaneously designed as receiver units 6, 7, 16 as well as three evaluation units 10, 11, 17. The transmitter units 2, 3 15 are designed and arranged in such a manner that they each transmit an electromagnetic measuring signal 4, 5, 18 in the form of a pulse-like radar signal in the direction of the object 20 whose distance from the transmitter units 2, 3, 15 is to be determined. The signal, which is received by the receiver unit 6, 7, 15 after reflection on the object 20, is forwarded to the evaluation unit 10, 11, 17. The receiver units 6, 7 are designed and arranged in such a manner that they at least partially receive the measuring and reflection signals of all transmitter units 2, 3, 15. This is illustrated as an example by the course of the measuring signal 13. Additionally, the transmitter and receiver units 6, 7, 16 have identical measuring frequency ranges. In order to avoid the transmitter and receiver units 6, 7, 16 from influencing one another, the operation of the transmitter units 2, 3, 15 is presently coordinated so that a clear assignment of each measuring and reflection signal 8, 9, 19 to one of the transmitter units 2, 3, 15 is possible. Presently, the transmitter units 2, 3, 15 communicate among one another via a wireless interface, via which the coordination of the operation of the transmitter units 2, 3, 15 is carried out in succession.

[0043] In the illustrated embodiment, the coordination of the operation of the individual transmitter units 2, 3, 15 is carried out in such a manner that only one, single transmitter unit 2, 3, 15 is active at a time. At the same time, the associated receiver unit 6, 7, 16 is active only when the transmitter unit 2, 3, 15 identical to it is active. Subsequently, it is ensured that a receiver unit 6, 7, 16 does not register measuring signals 13 transmitted by a transmitter unit 2, 3, 15 that is not identical to this receiver unit.

[0044] As a result, the embodiment illustrated in FIG. 2 also provides a device 1 for measuring the distance to an object 20, which has a particularly high measuring accuracy and operating safety by using three transmitter units 2, 3, 15 and three receiver units 6, 7, 16, wherein failure-free operation of the transmitter and receiver units can be ensured.

[0045] FIG. 3, as an example, illustrates a diagram of the subdivision of a measuring frequency range, at frequencies in which the transmitter and receiver units are operated. The range 21 corresponds to the measuring frequency range. This range is subdivided into two measuring sub-bands 22, 23 that are each associated with one of the transmitter units 2, 3, 15. Furthermore, the illustrated measuring frequency range has a communication sub-band 24, the frequencies of which being transmitted or received by all transmitter and receiver units 6, 7, 16. During operation of a device 1, a receiver 6, 7, 16 can be informed solely by signals via the transmitting and receiving of frequencies within the communication sub-band 24 that transmitter units 2, 3, 15 are active.